1. Field of the Invention
The present invention relates to a jet apparatus for treating a yarn with a treatment fluid, such as hot gas or steam, and in particular, to a jet apparatus that includes a flow control plate whereby the supply of treatment fluid to the jet may be adjustably controlled.
2. Description of the Prior Art
In the manufacture of synthetic thermoplastic yarn it is known that bulk and interlace may be imparted to the yarn by directing a heated treatment fluid to opposite sides of a yarn as it travels along a passage formed within a jet body. U.S. Pat. No. 3,525,134 (Coon) exemplifies such a dual impingement yarn treatment jet. The jet structure is formed from a jet body having a conjoinable cover. One surface of the jet body has the yarn passage and associated lateral supply conduits precisely machined therein. Treatment fluid is supplied to the lateral supply conduits from supply channels that extend into the jet body from the machined surface. The supply channels typically communicate with a common supply manifold. The supply manifold may be bored into the jet body or formed in a separate manifold body which is itself attachable to the jet body. The relative sizing of the various regions of the yarn passage and the associated conduits and supply channels permits the flow of treatment fluid impinging on the yarn to be precisely controllable. Owing to the care which must be exercised in forming the passage and associated conduits and channels, fabrication of a yarn treatment jet is time consuming and expensive.
In some instances, however, it may occur that the amount of interlace imparted to a yarn by a jet may become excessive. Of course, replacing the jet body with an alternative jet which is engineered to produce a different level of interlace is a direct expedient for altering the interlace level. However, owing to the cost associated with the fabrication of a jet, this alternative is not seen as economically favorable.
Alternatively, it is known that an imbalance in the flow of treatment fluid to opposite sides of the yarn has the effect of reducing the amount of interlace imparted to the yarn. U.S. Pat. No. 5,325,572 (Dickson et al.), assigned to the assignee of the present invention, discloses a jet structure having flow adjustment devices arranged to alter flow through the fluid supply channels and/or in the supply conduits.
In view of the foregoing it is believed desirable to provide an alternative jet structure wherein the flow of treatment fluid may be more easily adjusted so that the relative balance between the flow to the two opposing sides of the yarn may be selectably controlled.